Endothelin-1 inhibits endothelin-converting enzyme-1 expression in cultured rat pulmonary endothelial cells.
BACKGROUND
The lung expresses large amounts of endothelin-converting enzyme-1 (ECE-1), which catalyzes a step in the biosynthesis of potent vasoactive endothelin-1 (ET-1) from the inactive intermediate big ET-1. Because there has been no report concerning a possible relationship between ET-1 and ECE-1, we investigated the effects of ET-1 on ECE-1 expression in cultured rat pulmonary endothelial cells.


RESULTS
ECE-1 messenger RNA (mRNA) and protein expression in cultured endothelial cells were assayed by Northern and Western blotting, respectively. Incubation with ET-1 for 6 hours caused a significant decrease in ECE-1 mRNA expression. The action of ET-1 on ECE-1 mRNA expression was antagonized by pretreatment with BQ788, a specific ETB receptor antagonist, but not by pretreatment with BQ123, a specific ETA receptor antagonist. The expression of ECE-1 protein was also inhibited at 6 hours after incubation with ET-1. The effects of ET-1 on ECE-1 mRNA and protein expression were shown to be mimicked by ionomycin, a calcium ionophore, but not by 12-O-tetradecanoylphorbol 13-acetate, a protein kinase C activator.


CONCLUSIONS
The present results demonstrate that ET-1 suppressed ECE-1 protein levels by inhibiting ECE-1 mRNA expression through the ETB receptor, suggesting the existence of a feedback action of ET-1 on ECE-1 in pulmonary endothelial cells.
Naomi
S
S
Third Department of Internal Medicine, Kumamoto University School of Medicine, Honjo, Japan.
Iwaoka
T
T
Disashi
T
T
Inoue
J
J
Kanesaka
Y
Y
Tokunaga
H
H
Tomita
K
K
D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000037:antagonists & inhibitors* / Q000235:genetics; D002273:Carcinogens / Q000494:pharmacology; D002460:Cell Line; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1 / Q000494:pharmacology*; D000072396:Endothelin-Converting Enzymes; D004730:Endothelium, Vascular / Q000166:cytology / Q000201:enzymology*; D015971:Gene Expression Regulation, Enzymologic; D015759:Ionomycin / Q000494:pharmacology; D007476:Ionophores / Q000494:pharmacology; D008168:Lung / Q000166:cytology* / Q000201:enzymology; D008666:Metalloendopeptidases; D009842:Oligopeptides / Q000494:pharmacology; D010456:Peptides, Cyclic / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D051381:Rats; D013755:Tetradecanoylphorbol Acetate / Q000031:analogs & derivatives / Q000494:pharmacology; D013997:Time Factors
D002273:Carcinogens; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1; D007476:Ionophores; D009842:Oligopeptides; D010456:Peptides, Cyclic; D010880:Piperidines; D012333:RNA, Messenger; C086539:BQ 788; D015759:Ionomycin; D016282:Aspartic Acid Endopeptidases; D008666:Metalloendopeptidases; D000072396:Endothelin-Converting Enzymes; D013755:Tetradecanoylphorbol Acetate; C072247:cyclo(Trp-Asp-Pro-Val-Leu)